1. When calling c->set_config_path(), update configfile.  I.e. if we
are setting the config_path to /var/lib/lxc, then the configfile should
be changed to /var/lib/lxc/$container/config

2. Add an optional configpath argument to lxc_container_new.  If NULL,
then the default will be used (as before).  If set, then the passed-in
path will be used.  This way you can do

	c1 = lxc.Container("r1", "/var/lib/lxc");
	c2 = lxc.Container("r2", "/home/user/lxcbase");

(Note I did *not* implement the python or lua binding to pass that
argument along)
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>